Developing cartridge including inclined surface movable together with casing and developing roller relative to photosensitive drum

ABSTRACT

The developing cartridge includes a casing, a developing roller, and a first inclined surface. The first inclined surface is positioned at an outer surface of one end portion of the casing in the second direction. The first inclined surface is fixed to the casing and is inclined relative to the first direction. The first inclined surface is movable in the first direction relative to the photosensitive drum between a first position and a second position together with the casing and the developing roller in a state where the developing cartridge 1 is attached to a drum cartridge. In a state where the first inclined surface is at the first position, the developing roller is in contact with the photosensitive drum. In a state where the first inclined surface is at the second position, the developing roller is in separation from the photosensitive drum.

CROSS REFERENCE TO RELATED APPLICATION

This is a by-pass continuation application of International ApplicationNo. PCT/JP2020/005475 filed Feb. 13, 2020 claiming priority fromJapanese Patent Application No. 2019-063303 filed Mar. 28, 2019. Theentire contents of the International Application and the priorityapplication are incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to a developing cartridge.

BACKGROUND

Conventionally, there have been known electro-photographic typeimage-forming apparatuses such as a laser printer and an LED printer.Such conventional image-forming apparatuses include a developingcartridge. The developing cartridge includes a developing roller forsupplying developing agent. One of the conventional image-formingapparatuses includes a drum cartridge. The drum cartridge includes aphotosensitive drum. The developing cartridge is attached to the drumcartridge. When the developing cartridge is attached to the drumcartridge, the photosensitive drum and the developing roller contacteach other.

SUMMARY

The above-described conventional image-forming apparatus is switchablebetween a state where the developing roller and the photosensitive drumare in contact with each other and a state where the developing rollerand the photosensitive drum are spaced apart from each other. In thisconventional image-forming apparatus, components for moving thedeveloping cartridge to separate the developing roller from thephotosensitive drum are provided at each side of a drum unit. Therefore,the components at each side need to receive a driving force from a mainbody of the image-forming apparatus.

In view of the foregoing, it is an object of the present disclosure toprovide a developing cartridge capable of separating a developing rollerfrom a photosensitive drum by application of a driving force only to oneside, without necessitating application of a driving force to each side.

In order to attain the above and other objects, according to one aspect,the present disclosure provide a developing cartridge including acasing, a developing roller, and a first inclined surface. Thedeveloping cartridge is attachable to a drum cartridge including aphotosensitive drum. The casing is configured to accommodate thereindeveloping agent. The developing roller is rotatable about a developingroller axis extending in a first direction. The developing roller iscontactable with the photosensitive drum. The developing roller has acircumferential surface having one side portion and another side portionin a second direction crossing the first direction. The one side portionis exposed to an outside of the casing and the another side portion ispositioned inside the casing. The first inclined surface is positionedat an outer surface of one end portion of the casing in the seconddirection. The first inclined surface is fixed to the casing andinclined relative to the first direction. In a state where thedeveloping cartridge is attached to the drum cartridge, the firstinclined surface is movable together with the casing and the developingroller in the first direction relative to the photosensitive drumbetween a first position and a second position. In a state where thefirst inclined surface is at the first position, the developing rolleris in contact with the photosensitive drum. In a state where the firstinclined surface is at the second position, the developing roller is inseparation from the photosensitive drum.

BRIEF DESCRIPTION OF THE DRAWINGS

The particular features and advantages of the embodiment(s) as well asother objects will become apparent from the following description takenin connection with the accompanying drawings, in which:

FIG. 1 is a schematic diagram of an image-forming apparatus;

FIG. 2 is a perspective view of a developing cartridge according to afirst embodiment;

FIG. 3 is a schematic view illustrating one end portion of a developingroller in a first direction;

FIG. 4 is a view of the drum cartridge as viewed in a third directiontoward one side from another side and illustrates a state where thedeveloping cartridges according to the first embodiment are attached tothe drum cartridge;

FIG. 5 is an enlarged perspective view of a contact surface (i.e., anouter circumferential surface of a first guide roller);

FIG. 6 is an enlarged perspective view of a contact surface (i.e., anouter circumferential surface of a second guide roller);

FIG. 7 is a view of the developing cartridge and the photosensitive drumin a contacting state as viewed in the third direction toward the oneside from the other side in the first embodiment;

FIG. 8 is a view of the developing cartridge and the photosensitive drumin the contacting state as viewed in the first direction toward one sidefrom another side in the first embodiment;

FIG. 9 is a perspective view of the developing cartridge and thephotosensitive drum in the contacting state in the first embodiment;

FIG. 10 is a view of the developing cartridge and the photosensitivedrum in a separated state as viewed in the third direction toward theone side from the other side in the first embodiment;

FIG. 11 is a view of the developing cartridge and the photosensitivedrum in the separated state as viewed in the first direction toward theone side from the other side in the first embodiment;

FIG. 12 is a perspective view of the developing cartridge and thephotosensitive drum in the separated state in the first embodiment;

FIG. 13 is a perspective view of a developing cartridge according to asecond embodiment;

FIG. 14 is a cross-sectional view of the developing cartridge accordingto the second embodiment in a contacting state, taken along a planeperpendicular to the third direction;

FIG. 15 is a view of the developing cartridge according to the secondembodiment in the contacting state as viewed in the first direction fromthe other side to the one side;

FIG. 16 is a perspective view of the developing cartridge according tothe second embodiment in the contacting state;

FIG. 17 is a cross-sectional view of the developing cartridge accordingto the second embodiment in a separated state, taken along a planeperpendicular to the third direction;

FIG. 18 is a view of the developing cartridge according to the secondembodiment in the separated state as viewed in the first direction fromthe other side to the one side; and

FIG. 19 is a perspective view of the developing cartridge according tothe second embodiment in the separated state.

DETAILED DESCRIPTION

Embodiments of the present disclosure will be described while referringto the accompanying drawings.

In the following description, a direction in which a rotation axis (adeveloping roller axis) of a developing roller extends will be referredto as “first direction.” Here, an outer circumferential surface of thedeveloping roller has a portion exposed to an outside of a casing, andanother portion accommodated inside the casing. A direction in which theexposed portion and the accommodated portion of the circumferentialsurface are arranged will be referred to as “second direction.” Thefirst direction and the second direction cross each other. Preferably,the first direction and the second direction are orthogonal to eachother. Furthermore, a direction crossing both the first direction andthe second direction (preferably, orthogonal to both the first directionand the second direction) will be referred to as a “third direction.”

First Embodiment 1. Outline of Structure of Image-Forming Apparatus

FIG. 1 is a schematic diagram of an image-forming apparatus 100. Theimage-forming apparatus 100 is an electro-photographic type printer.Examples of the image-forming apparatus 100 include a laser printer andan LED printer. As illustrated in FIG. 1 , the image-forming apparatus100 includes four developing cartridges 1, a drum cartridge 2, and amain body 9.

1-1. Outline of Structure of Main Body

The structure of the main body 9 of the image-forming apparatus 100 willbe outlined. As illustrated in FIG. 1 , the main body 9 includes a mainbody frame 101, a transfer belt (not illustrated), and a controller 102.

The main body frame 101 has a generally rectangular parallelepipedshape. The main body frame 101 has an internal space. In a state wherethe developing cartridges 1 are attached to the drum cartridge 2, thedrum cartridge 2 is attached in the internal space of the main bodyframe 101. Further, four chargers (not illustrated), four light sources(not illustrated), the transfer belt, and the controller 102 areattached in the main body frame 101.

The transfer belt is an endless belt for conveying a printing sheet. Ina state where the drum cartridge 2 is attached in the internal space ofthe main body frame 101 with the developing cartridges 1 attached to thedrum cartridge 2, the transfer belt is positioned at the opposite sideto developing rollers 30 with respect to photosensitive drums 21. Theouter peripheral surface of the transfer belt is contactable with theouter circumferential surfaces of the photosensitive drums 21.

The controller 102 includes a processor such as CPU, and a main bodymemory. The main body memory is a readable and writable storage mediumsuch as a flash ROM and EEPROM. The main body memory stores thereincomputer programs for controlling operations of the image-formingapparatus 100. The processor is configured to execute various processesin accordance with the computer programs stored in the main body memory.That is, the processor is configured to execute a printing process andvarious processes attendant thereto performed by the image-formingapparatus 100.

1-2. Outline of Structure of Developing Cartridge

The structure of the developing cartridge 1 will be outlined whilereferring to FIGS. 1 to 3 . FIG. 2 is a perspective view of thedeveloping cartridge 1. FIG. 3 is a schematic view illustrating one endportion of the developing roller 30 in the first direction.

As illustrated in FIG. 1 , the developing cartridge 1 is attachable toand detachable from a drum frame 200 of the drum cartridge 2. Asillustrated in FIG. 2 , the developing cartridge 1 includes a casing 10configured to accommodate therein developing agent.

The casing 10 includes a container 10A and a lid 10B. The container 10Ahas an internal space. The lid 10B is a flat plate shape. The lid 10B ispositioned at one end portion of the casing 10 in the second direction.The lid 10B has a third outer surface 13 described later. The lid 10Bcovers an opening portion formed at one end portion of the container 10Ain the second direction. The container 10A has an opening 10C formed atone end portion of the container 10A in the third direction. Thedeveloping roller 30 is positioned at the opening 10C.

The casing 10 has one end portion and another end portion in the firstdirection. The other end portion of the casing 10 in the first directionhas a first outer surface 11, and the one end portion of the casing 10in the first direction has a second outer surface 12. Further, thecasing 10 has the third outer surface 13 and a fourth outer surface 14(FIG. 7 ) which are spaced apart from each other in the seconddirection. The third outer surface 13 is positioned at the one endportion of the casing 10 in the second direction. The fourth outersurface 14 is positioned at another end portion of the casing 10 in thesecond direction.

The four developing cartridges 1 accommodate therein developing agent ofdifferent colors (for example, cyan, magenta, yellow and black).However, the four developing cartridges 1 may accommodate thereindeveloping agent of identical color. For example, the developing agentis toner.

The developing cartridge 1 further includes the developing roller 30.The developing roller 30 is a member having a cylindrical shape. Thedeveloping roller 30 is rotatable about a developing roller axis whichis a rotation axis extending in the first direction. The developingroller 30 is supported by the casing 10 so as to be rotatable about thedeveloping roller axis.

The developing roller 30 includes a roller body 31 and a developingroller shaft 32. The roller body 31 is a cylindrical member extending inthe first direction. The roller body 31 is made of elastic material suchas rubber. The developing roller shaft 32 is a solid cylindrical memberpenetrating the roller body 31 in the first direction. The developingroller shaft 32 is made of metal or electrically conductive resin. Theroller body 31 is fixed to the developing roller shaft 32 so as not torotate relative to the developing roller shaft 32. That is, the rollerbody 31 is rotatable together with the developing roller shaft 32 aboutthe developing roller axis. The circumferential surface of the rollerbody 31 has one side portion and another side portion in the seconddirection. The one side portion of the circumferential surface of theroller body 31 in the second direction is exposed to an outside of thecasing 10 through the opening 10C. The other side portion of thecircumferential surface of the roller body 31 in the second direction ispositioned inside the casing 10.

The developing roller shaft 32 has one end portion and another endportion in the first direction. A developing roller gear (notillustrated) is attached to the other end portion of the developingroller shaft 32 in the first direction. The developing roller gear ispositioned at the first outer surface 11. The developing roller shaft 32is fixed to the developing roller gear so as not to rotate relative tothe developing roller gear. Hence, when the developing roller gearrotates, the developing roller shaft 32 and the roller body 31 rotatetogether with the developing roller gear.

As illustrated in FIG. 3 , a collar 33 having a cylindrical shape ispositioned at the one end portion of the developing roller shaft 32 inthe first direction. The one end portion of the developing roller shaft32 in the first direction is positioned in the collar 33. The collar 33is electrically connected to the developing roller 30. The collar 33 hasone end face and another end face in the first direction. The collar 33has an elastic member accommodating portion 33 a. The elastic memberaccommodating portion 33 a has a cylindrical shape and is recessed fromthe other end face in the first direction toward one side from anotherside. The elastic member accommodating portion 33 a has a bottom portion33 b.

The developing roller shaft 32 has a retaining ring 34. The one endportion of the developing roller shaft 32 in the first direction isfitted with the retaining ring 34. The retaining ring 34 is positionedfurther in the first direction toward the other side from the one sidethan the collar 33.

The developing roller shaft 32 includes an elastic member 35. Theelastic member 35 is a coil spring formed by helically winding a metalwire. The elastic member 35 has one end connected to the bottom portion33 b of the elastic member accommodating portion 33 a. The elasticmember 35 has another end connected to the retaining ring 34.

The developing roller shaft 32 may not penetrate the roller body 31 inthe first direction. For example, the developing roller shaft 32 mayextend in the first direction from each end of the roller body 31 in thefirst direction.

As illustrated in FIG. 2 , the developing cartridge 1 includes a gearportion 40. The gear portion 40 is positioned at the first outer surface11 of the casing 10. The gear portion 40 includes a coupling 41, thedeveloping roller gear, and a gear cover 43.

The coupling 41 is a rotary body configured to receive a driving forcesupplied from the image-forming apparatus 100. The coupling 41 isrotatable about a rotation axis extending in the first direction. Thecoupling 41 has a fixing hole 411 recessed in the first direction. Whenthe drum cartridge 2 in a state where the developing cartridge 1 isattached thereto is attached in the main body 9 of the image-formingapparatus 100, a transmission shaft (not illustrated) of the main body 9is inserted into the fixing hole 411. Hence, the transmission shaft andthe coupling 41 are coupled together so as not to rotate relative toeach other. Accordingly, when the transmission shaft rotates, thecoupling 41 rotates. When the coupling 41 rotates, the developing rollergear rotates. The developing roller 30 also rotates together with thedeveloping roller gear. Further, when the coupling 41 rotates, a supplyroller (not illustrated) and an agitator (not illustrated) also rotate.

The casing 10 includes a handle 38 for a user to grip. The handle 38 ispositioned at an outer surface at another end portion of the casing 10in the third direction.

1-3. Outline of Structure of Drum Cartridge

The structure of the drum cartridge 2 will be outlined while referringto FIGS. 1 and 4 . FIG. 4 is a view of the drum cartridge 2 as viewed inthe third direction toward one side from another side and illustrates astate where the developing cartridges 1 are attached to the drumcartridge 2. The drum cartridge 2 includes four photosensitive drums 21,and the drum frame 200.

Each of the four photosensitive drums 21 illustrated in FIG. 1 has anouter circumferential surface having a cylindrical shape whose center isa drum axis which is a rotation axis extending in the first direction.The outer circumferential surfaces of the photosensitive drums 21 arecoated with photosensitive material. Each of the four photosensitivedrums 21 is rotatable about the drum axis.

The drum frame 200 is a frame holding the four photosensitive drums 21.The drum frame 200 holds the photosensitive drums 21 in a state wherethe photosensitive drums 21 are spaced apart from one another in thesecond direction. The drum frame 200 includes a pair of side frames 201,202 facing each other in the first direction. The side frame 202 ispositioned in the first direction from the other side toward the oneside than the side frame 201. Each photosensitive drum 21 is rotatablysupported by the side frames 201 and 202.

In a state where the developing cartridge 1 is attached to the drumframe 200, the one end portion of the developing roller shaft 32 in thefirst direction faces the side frame 202. Specifically, as illustratedin FIG. 3 , the collar 33 positioned at the one end portion of thedeveloping roller shaft 32 in the first direction contacts an innersurface of the side frame 202. The collar 33 is pressed in the directionfrom the one side toward the other side by the contact between the sideframe 202 and one end portion of the collar 33 in the first direction.Hence, the collar 33 moves on the developing roller shaft 32 in thefirst direction toward the other side from the one side. Accordingly, adistance between the bottom portion 33 b and the retaining ring 34 isdecreased, so that the elastic member 35 falls in a compressed statewhere its length is smaller than its natural length. Thus, the elasticmember 35 urges, through the retaining ring 34, the developing rollershaft 32 in the first direction toward the other side from the one side.Consequently, the first outer surface 11 of the developing cartridge 1is positioned in the vicinity of the inner surface of the side frame201. In this way, the position of the developing cartridge 1 in thefirst direction relative to the drum cartridge 2 is fixed.

For performing a printing process in the image-forming apparatus 100,the controller 102 drives a motor (not illustrated). By the drive of themotor, the photosensitive drum 21 and the developing roller 30 rotatethrough the transmission shaft and the coupling 41. The controller 102also supplies electric power to a charger (not illustrated) to chargethe outer circumferential surface of the photosensitive drum 21.Further, the controller 102 turns on a light source (not illustrated) toirradiate the outer circumferential surface of the photosensitive drum21 with the light of the light source. Thus, an electrostatic latentimage corresponding to an image to be printed is formed on the outercircumferential surface of the photosensitive drum 21. The developingagent accommodated in the developing cartridge 1 is supplied through thedeveloping roller 30 to the electrostatic latent image formed on thephotosensitive drum 21. Thus, the electrostatic latent image becomes avisible developing agent image on the outer circumferential surface ofthe photosensitive drum 21. Then, the printing sheet is conveyed to aportion between the photosensitive drum 21 and the transfer belt. Hence,the developing agent image is transferred from the outer circumferentialsurface of the photosensitive drum 21 onto the printing sheet. In astate where the developing agent image is transferred to the printingsheet, the printing sheet is conveyed to a fixing unit (not illustrated)provided in the image-forming apparatus 100. Accordingly, the developingagent image transferred to the printing sheet is thermally fixed to theprinting sheet. As a result, the image is printed on the printing sheet.

In the image forming apparatus 100, it is preferable that each of thedeveloping rollers 30 be separated from the corresponding one of thephotosensitive drums 21 during switch of printing colors or during astandby period in a printing process. To this end, the image-formingapparatus 100 in the present embodiment has a contacting state and aseparated state.

The contacting state is a state where each of the developing rollers 30is in contact with the corresponding one of the photosensitive drums 21in a state where the four developing cartridges 1 are attached to thedrum cartridge 2. The separated state is a state where each of thedeveloping rollers 30 is separated from the corresponding one of thephotosensitive drums 21 in the state where the four developingcartridges 1 are attached to the drum cartridge 2.

To this effect, as components for the contact and the separation, eachof the developing cartridges 1 further includes a first cam 61 and asecond cam 62. The first cam 61 has a first inclined surface 61 a. Thesecond cam 62 has a second inclined surface 62 a and a pressurereceiving surface 62 b. Moreover, as components for the contact and theseparation, the drum cartridge 2 includes a first guide roller 24 and asecond guide roller 25 for each of the four developing cartridges 1.Furthermore, as components for the contact and the separation, the mainbody 9 of the image-forming apparatus 100 includes a drive shaft 103 foreach of the four developing cartridges 1.

2. Components in Drum Cartridge for Contact and Separation

The components which the drum cartridge 2 includes for performing thecontact and the separation will be described while referring to FIGS. 4through 6 .

In a state where the developing cartridge 1 is attached to the drumcartridge 2, the first outer surface 11 of the developing cartridge 1faces the inner surface of the first side frame 201 in the firstdirection. In the state where the developing cartridge 1 is attached tothe drum cartridge 2, the second outer surface 12 of the developingcartridge 1 faces the inner surface of the second side frame 202 in thefirst direction.

As indicated by a broken line in an enlarged view depicted in the lowerpart of FIG. 4 , the first side frame 201 includes the first guideroller 24. That is, the first guide roller 24 is positioned at anotherend portion of the drum frame 200 in the first direction.

FIG. 5 is an exploded perspective view illustrating the first guideroller 24 and a bearing portion 26 supporting the first guide roller 24.As illustrated in FIG. 5 , the first guide roller 24 has an outercircumferential surface (a contact surface) 240 having a cylindricalshape extending in the third direction. Each end portion of the firstguide roller 24 in the third direction is rotatably supported by thebearing portion 26. Hence, the first guide roller 24 is rotatable aboutits center axis extending in the third direction.

As indicated by a broken line in an enlarged view depicted in the upperpart of FIG. 4, the second side frame 202 includes the second guideroller 25. That is, the second guide roller 25 is positioned at one endportion of the drum frame 200 in the first direction.

FIG. 6 is an exploded perspective view illustrating the second guideroller 25 and a bearing portion 27 supporting the second guide roller25. As illustrated in FIG. 6 , the second guide roller 25 has an outercircumferential surface (a contact surface) 250 having a cylindricalshape extending in the third direction. Each end portion of the secondguide roller 25 in the third direction is rotatably supported by thebearing portion 27. Hence, the second guide roller 25 is rotatable aboutits center axis extending in the third direction.

The first guide roller 24 and the second guide roller 25 are positionedso as to function as a roller pair in the first direction. As describedlater, the second inclined surface 62 a of the second cam 62 iscontactable with the outer circumferential surface 240 of the firstguide roller 24, and the first inclined surface 61 a of the first cam 61is contactable with the outer circumferential surface 250 of the secondguide roller 25.

3. Components in Main Body for Contact and Separation

The components which the main body 9 of the image-forming apparatus 100includes for performing the contact and the separation will be describedwhile referring to FIGS. 7 and 8 . The main body 9 of the image-formingapparatus 100 includes the drive shaft 103 for each of the fourdeveloping cartridges 1. The drive shaft 103 is a solid cylinder orsolid prismatic column extending in the first direction. The drive shaft103 advances and retracts in the first direction by receiving a drivingforce from the main body 9.

4. Components in Developing Cartridge for Contact and Separation

The components which the developing cartridge 1 includes for performingthe contact and the separation will be described while referring toFIGS. 2 and 7 through 9 . FIG. 7 is a view of the developing cartridge 1and the photosensitive drum 21 in the contacting state as viewed in thethird direction from the other side toward the one side in the presentembodiment. FIG. 8 is a view of the developing cartridge 1 and thephotosensitive drum 21 in the contacting state as viewed in the firstdirection from the other side toward the one side in the presentembodiment. FIG. 9 is a perspective view of the developing cartridge 1and the photosensitive drum 21 in the contacting state in the presentembodiment.

The first cam 61 illustrated in FIGS. 7 and 9 has a right-angledtriangular prism shape. The first cam 61 has the first inclined surface61 a. The first inclined surface 61 a is positioned at the third outersurface 13 of the one end portion of the casing 10 in the seconddirection. The first inclined surface 61 a is fixed to the casing 10.The first inclined surface 61 a is inclined relative to the firstdirection.

Specifically, the first inclined surface 61 a has one end edge 61 b andanother end edge 61 c in the first direction. A distance in the seconddirection between the one end edge 61 b of the first inclined surface 61a and the third outer surface 13 (specifically, the outer surface of thelid 10B) of the one end portion of the casing 10 in the second directionis defined as a first distance L1. A distance in the second directionbetween the other end edge 61 c of the first inclined surface 61 a andthe third outer surface 13 (specifically, the outer surface of the lid10B) of the one end portion of the casing 10 in the second direction isdefined as a second distance L2. The first distance L1 is smaller thanthe second distance L2 (L1<L2). That is, the first inclined surface 61 ais inclined so as to be distant in the second direction from the thirdouter surface 13 (specifically, the outer surface of the lid 10B) of theone end portion of the casing 10 in the second direction as extendingfrom the one end edge 61 b of the first inclined surface 61 a to theother end edge 61 c of the first inclined surface 61 a.

In a state where the developing cartridge 1 is attached to the drumcartridge 2, the first inclined surface 61 a is movable together withthe casing 10 and the developing roller 30 in the first directionrelative to the photosensitive drum 21 between a first position and asecond position.

The second cam 62 illustrated in FIGS. 7 and 9 has a semi-frustoconicalshape. The second cam 62 has the second inclined surface 62 a. Thesecond inclined surface 62 a is positioned at the third outer surface 13of the one end portion of the casing 10 in the second direction. Thesecond inclined surface 62 a is fixed to the casing 10. The secondinclined surface 62 a is inclined relative to the first direction.

Specifically, the second inclined surface 62 a has one end edge 62 c andanother end edge 62 d in the first direction. A distance in the seconddirection between the one end edge 62 c of the second inclined surface62 a and the third outer surface 13 (specifically, the outer surface ofthe lid 10B) of the one end portion of the casing 10 in the seconddirection is defined as a third distance L3. A distance in the seconddirection between the other end edge 62 d of the second inclined surface62 a and the third outer surface 13 (specifically, the outer surface ofthe lid 10B) of the one end portion of the casing 10 in the seconddirection is defined as a fourth distance L4. The third distance L3 issmaller than the fourth distance L4 (L3<L4). That is, the secondinclined surface 62 a is inclined so as to be distant in the seconddirection from the third outer surface 13 (specifically, the outersurface of the lid 10B) of the one end portion of the casing 10 in thesecond direction as extending from the one end edge 62 c of the secondinclined surface 62 a to the other end edge 62 d of the second inclinedsurface 62 a.

In a state where the developing cartridge 1 is attached to the drumcartridge 2, the second inclined surface 62 a is movable together withthe casing 10 and the developing roller 30 in the first directionrelative to the photosensitive drum 21 between a third position and afourth position.

The second cam 62 has the pressure receiving surface 62 b. The pressurereceiving surface 62 b is positioned at the first outer surface 11 ofthe casing 10. The pressure receiving surface 62 b is fixed to the gearcover 43. The pressure receiving surface 62 b is a flat surfaceperpendicular to the first direction.

The second inclined surface 62 a and the pressure receiving surface 62 bare different surfaces from each other in the outer surface of thesecond cam 62.

5. Movement of Each Component at the Time of Switching BetweenContacting State and Separated State

Movement of each component for the contact and the separation at thetime of switching the state of the image-forming apparatus 100 betweenthe contact state and the separated state will be described whilereferring to FIGS. 7 to 12 . FIG. 10 is a view of the developingcartridge 1 and the photosensitive drum 21 in the separated state asviewed in the third direction from the other side toward the one side inthe present embodiment. FIG. 11 is a view of the developing cartridge 1and the photosensitive drum 21 in the separated state as viewed in thefirst direction from the other side toward the one side in the presentembodiment. FIG. 12 is a perspective view of the developing cartridge 1and the photosensitive drum 21 in the separated state in the presentembodiment.

In the image-forming apparatus 100, the pressure receiving surface 62 bof the second cam 62 is pressed by the drive shaft 103 when the driveshaft 103 is driven to advance in a direction from the other end portionof the casing 10 in the first direction toward the one end portion ofthe casing 10 in the first direction. Hence, the pressure receivingsurface 62 b receives the pressing force directed from the other endportion of the casing 10 in the first direction toward the one endportion of the casing 10 in the first direction. Here, the pressurereceiving surface 62 b, the first inclined surface 61 a, and the secondinclined surface 62 a are fixed to the casing 10. Therefore, when thepressure receiving surface 62 b receives the pressing force, the firstinclined surface 61 a moves in the first direction from the firstposition illustrated in FIGS. 7 and 9 to the second position illustratedin FIGS. 10 and 12 . Further, when the pressure receiving surface 62 breceives the pressing force, the second inclined surface 62 a moves inthe first direction from the third position illustrated in FIGS. 7 and 9to the fourth position illustrated in FIGS. 10 and 12 .

In a process of the movement of the first inclined surface 61 a from thefirst position to the second position, the first inclined surface 61 acontacts the outer circumferential surface 250 of the second guideroller 25 of the drum cartridge 2. In accordance with the movement ofthe first inclined surface 61 a from the first position to the secondposition, the contacting position between the first inclined surface 61a and the second guide roller 25 gradually shifts on the first inclinedsurface 61 a from a position close to the one end edge 61 b to aposition close to the other end edge 61 c. Hence, a distance in thesecond direction between the outer surface of the lid 10B and thecontacting position at which the first inclined surface 61 a and thesecond guide roller 25 are in contact with each other graduallyincreases as the first inclined surface 61 a approaches the secondposition from the first position. As a result, since the first inclinedsurface 61 a is pressed by the second guide roller 25, the casing 10 andthe developing roller 30 gradually move together with the first cam 61relative to the photosensitive drum 21 in the second direction from oneside toward another side.

In a process of the movement of the second inclined surface 62 a fromthe third position to the fourth position, the second inclined surface62 a contacts the outer circumferential surface 240 of the first guideroller 24 of the drum cartridge 2. In accordance with the movement ofthe second inclined surface 62 a from the third position to the fourthposition, the contacting position between the second inclined surface 62a and the first guide roller 24 gradually shifts on the second inclinedsurface 62 a from a position close to the one end edge 62 c to aposition close to the other end edge 62 d. Hence, a distance in thesecond direction between the outer surface of the lid 10B and thecontacting position at which the second inclined surface 62 a and thefirst guide roller 24 are in contact with each other gradually increasesas the second inclined surface 62 a approaches the fourth position fromthe third position. As a result, since the second inclined surface 62 ais pressed by the first guide roller 24, the casing 10 and thedeveloping roller 30 gradually move together with the second cam 62relative to the photosensitive drum 21 in the second direction from theone side toward the other side.

As described above, since the first inclined surface 61 a is pressed bythe second guide roller 25, the one end portions of the casing 10 andthe developing roller 30 in the first direction are pushed out relativeto the photosensitive drum 21 in the second direction from the one sidetoward the other side. Further, since the second inclined surface 62 ais pressed by the first guide roller 24, the other end portions of thecasing 10 and the developing roller 30 in the first direction are pushedout relative to the photosensitive drum 21 in the second direction fromthe one side toward the other side. As a result, the developing roller30 can be separated from the photosensitive drum 21 while the developingcartridge 1 can be prevented from being inclined relative to the firstdirection.

That is, the developing roller 30 is in contact with the photosensitivedrum 21 when the first inclined surface 61 a is at the first positionand the second inclined surface 62 a is at the third position. Thedeveloping roller 30 is in separation from the photosensitive drum 21when the first inclined surface 61 a is at the second position and thesecond inclined surface 62 a is at the fourth position. Here, asillustrated in FIGS. 8 and 11 , the pressure receiving surface 62 b isoverlapped with the drive shaft 103 in the first direction in both caseswhere the first inclined surface 61 a is at the first position and atthe second position. In other words, the pressure receiving surface 62 bis overlapped with the drive shaft 103 as viewed in the first directionboth when the first inclined surface 61 a is at the first position andwhen the first inclined surface 61 a is at the second position. Further,the pressure receiving surface 62 b is a flat surface perpendicular tothe first direction. Hence, the pressure receiving surface 62 b can beslidingly moved relative to the drive shaft 103. As a result, shift fromthe contacting state to the separated state can be continuously andsmoothly performed in the image-forming apparatus 100.

In the image-forming apparatus 100, when the drive shaft 103 isretracted in a direction from the one end portion of the casing 10 inthe first direction toward the other end portion of the casing 10 in thefirst direction, the first outer surface 11 of the developing cartridge1 is pressed against the inner surface of the side frame 201 by theurging force of the elastic member 35 illustrated in FIG. 3 Hence, thefirst inclined surface 61 a moves from the second position to the firstposition in the first direction, and the second inclined surface 62 amoves from the fourth position to the third position in the firstdirection.

Here, the drum frame 200 of the drum cartridge 2 includes a pressuremechanism (not illustrated) for pressing the casing 10 of the developingcartridge 1 in a direction toward the photosensitive drum 21. Thedeveloping cartridge 1 is pushed by the pressure mechanism in the seconddirection from the other side toward the one side, so that thecontacting state where the developing roller 30 and the photosensitivedrum 21 is in contact with each other is restored. In this way, thestate of the image-forming apparatus 100 is switched between thecontacting state (FIGS. 6 through 8 ) and the separated state (FIGS. 9through 11 ).

6. Summary of First Embodiment

As described above, the developing cartridge 1 according to the firstembodiment includes the casing 10, the developing roller 30, and thefirst inclined surface 61 a. As illustrated in FIGS. 7 through 9 , inthe developing cartridge 1 according to the present embodiment, thedeveloping roller 30 is in contact with the photosensitive drum 21 in astate where the first inclined surface 61 a is at the first position. Asillustrated in FIGS. 10 through 12 , in the developing cartridge 1according to the present embodiment, the developing roller 30 is inseparation from the photosensitive drum 21 in a state where the firstinclined surface 61 a is at the second position. Hence, in a process ofmovement of the first inclined surface 61 a from the first position tothe second position, the first inclined surface 61 a is pressed by theouter circumferential surface (contact surface) 250 of the second guideroller 25 of the drum cartridge 2, so that the developing roller 30 canbe separated from the photosensitive drum 21.

In this way, in the developing cartridge 1 according to the presentembodiment, the developing roller 30 and the photosensitive drum 21 canbe separated from each other by application of a driving force only toone side in the first direction of the developing cartridge 1, withoutnecessitating application of a driving forces to each side of thedeveloping cartridge 1.

Further, in the developing cartridge 1 according to the presentembodiment, the first distance L1 is smaller than the second distance L2(L1<L2). Hence, in a process of movement of the first inclined surface61 a from the first position to the second position, the first inclinedsurface 61 a is gradually pressed in the second direction from the oneside toward the other side, so that the developing roller 30 can beseparated from the photosensitive drum 21.

The developing cartridge 1 according to the present embodiment furtherincludes the second inclined surface 62 a. As illustrated in FIGS. 7through 9 , in the developing cartridge 1 according to the presentembodiment, in a state where the first inclined surface 61 a is at thefirst position, the second inclined surface 62 a is at the thirdposition and the developing roller 30 is in contact with thephotosensitive drum 21. As illustrated in FIGS. 10 through 12 , in thedeveloping cartridge 1 according to the present embodiment, in a statewhere the first inclined surface 61 a is at the second position, thesecond inclined surface 62 a is at the fourth position and thedeveloping roller 30 is in separation from the photosensitive drum 21.Accordingly, in a process in which the first inclined surface 61 a movesfrom the first position to the second position and the second inclinedsurface 62 a moves from the third position to the fourth position, thefirst inclined surface 61 a and the second inclined surface 62 a arepressed by the outer circumferential surface 250 (contact surface) ofthe second guide roller 25 and the outer circumferential surface 240(contact surface) of the first guide roller 24, respectively. As aresult, the developing roller 30 can be separated from thephotosensitive drum 21. Since the first inclined surface 61 a and thesecond inclined surface 62 a are positioned away from each other in thefirst direction, the end portions of the casing 10 in the firstdirection can be pressed by the outer circumferential surfaces 240 and250 of the guide rollers 24 and 25.

Further, in the developing cartridge 1 according to the presentembodiment, the third distance L3 is smaller than the fourth distance L4(L3<L4). Hence, in a process of movement of the second inclined surface62 a from the third position to the fourth position, the second inclinedsurface 62 a is gradually pressed in the second direction from the oneside toward the other side, so that the developing roller 30 can beseparated from the photosensitive drum 21.

The developing cartridge 1 according to the present embodiment furtherincludes the pressure receiving surface 62 b. Hence, by the pressurereceiving surface 62 b being applied with a pressing force, the firstinclined surface 61 a can be moved together with both the casing 10 andthe developing roller 30.

Further, in the developing cartridge 1 according to the presentembodiment, the first inclined surface 61 a moves from the firstposition to the second position when the pressure receiving surface 62 breceives a pressing force directed from the other end portion of thecasing 10 in the first direction toward the one end portion of thecasing 10 in the first direction. Here, the pressing force directed fromthe other end portion to the one end portion of the casing 10 in thefirst direction is converted to a force directed in the second directionby the contact between the first inclined surface 61 a and the outercircumferential surface 250 of the second guide roller 25. As a result,the developing roller 30 can be separated from the photosensitive drum21.

Further, in the present embodiment, the main body 9 includes the driveshaft 103. The first inclined surface 61 a moves from the first positionto the second position when the drive shaft 103 presses the pressurereceiving surface 62 b. Thus, the developing roller 30 can be separatedfrom the photosensitive drum 21 by the driving force applied from themain body 9.

Further, in the developing cartridge 1 according to the presentembodiment, the developing roller 30 includes the roller body 31 and thedeveloping roller shaft 32. The developing cartridge 1 according to thepresent embodiment includes the collar 33 and the elastic member 35. Ina state where the drum cartridge 2 is attached to the main body 9 withthe developing cartridge 1 attached to the drum cartridge 2, the elasticmember 35 urges the developing roller 30 in a direction from the one endportion of the casing 10 in the first direction toward the other endportion of the casing 10 in the first direction. Hence, the firstinclined surface 61 a can be moved from the second position to the firstposition by the urging force of the elastic member 35. As a result, thedeveloping roller 30 can be moved from a state where the developingroller 30 is in separation from the photosensitive drum 21 to a statewhere the developing roller 30 is in contact with the photosensitivedrum 21.

Further, in the developing cartridge 1 according to the presentembodiment, the collar 33 is electrically connected to the developingroller 30. Hence, the collar 33 also functions as an electrode of thedeveloping roller 30, thereby reducing numbers of components.

Further, in the developing cartridge 1 according to the presentembodiment, the direction in which the elastic member 35 urges thedeveloping roller 30 is opposite to the direction in which the driveshaft 103 presses the pressure receiving surface 62 b. Hence, the firstinclined surface 61 a can be moved between the first position and thesecond position with high accuracy.

Further, in the developing cartridge 1 according to the presentembodiment, the first inclined surface 61 a moves from the secondposition to the first position by the urging force of the elastic member35 when a supply of the driving force from the main body 9 to the driveshaft 103 is stopped. Hence, by stopping the supply of the driving forcefrom the main body 9 to the drive shaft 103, the developing roller 30can be easily shifted from the state where the developing roller 30 isin separation from the photosensitive drum 21 to the state where thedeveloping roller 30 is in contact with the photosensitive drum 21.

Further, in the present embodiment, the drum cartridge 2 includes thesecond guide roller 25 having the outer circumferential surface 250which is contactable with the first inclined surface 61 a. Hence, thefirst inclined surface 61 a moves in the first direction whilemaintaining the contact with the outer circumferential surface 250 ofthe second guide roller 25, whereby the first inclined surface 61 a ispressed by the outer circumferential surface 250. As a result, thedeveloping roller 30 can be moved from the state where the developingroller 30 is in contact with the photosensitive drum 21 to the statewhere the developing roller 30 is in separation from the photosensitivedrum 21.

Further, in the present embodiment, the pressure receiving surface 62 bis the flat surface perpendicular to the first direction. Hence, thepressure receiving surface 62 b can easily be slidingly moved relativeto the drive shaft 103 in the second direction. As a result, thedeveloping roller 30 can be smoothly shifted from the state where thedeveloping roller 30 is in contact with the photosensitive drum 21 tothe state where the developing roller 30 is in separation from thephotosensitive drum 21.

Further, in the present embodiment, the pressure receiving surface 62 bis overlapped with the drive shaft 103 in the first direction in bothwhen the first inclined surface 61 a is at the first position and whenthe first inclined surface 61 a is at the second position. In otherwords, the pressure receiving surface 62 b is overlapped with the driveshaft 103 as viewed in the first direction in both the two cases. Hence,by slidingly moving the pressure receiving surface 62 b relative to thedrive shaft 103, the state of the developing roller 30 can becontinuously shifted between the state where the developing roller 30 isin contact with the photosensitive drum 21 and the state where thedeveloping roller 30 is in separation from the photosensitive drum 21.

Further, in the present embodiment, the second guide roller 25 isrotatable about the rotation axis extending in the third direction. Thisconfiguration can reduce frictional force generated between the firstinclined surface 61 a and the outer circumferential surface 250 of thesecond guide roller 25 when the first inclined surface 61 a moves in thefirst direction while contacting the outer circumferential surface 250of the second guide roller 25.

Second Embodiment

A developing cartridge 4 according to a second embodiment of the presentdisclosure will next be described with reference to FIGS. 13 through 19. FIG. 13 is a perspective view of the developing cartridge 4 accordingto the present embodiment.

The second embodiment mainly differs from the first embodiment in thatthe developing cartridge 4 has a recess 262 instead of the second cam62, and in that the drum cartridge 2 does not include the first guideroller 24. In the following description to the second embodiment, likeparts and components are designated by the same reference numerals asthose shown in the first embodiment to avoid duplicating description.

7. Specific Structure of Second Embodiment

The gear cover 43 of the developing cartridge 4 has the recess 262. Therecess 262 is recessed in a direction toward one end portion of the gearcover 43 in the first direction from another end portion of the gearcover 43 in the first direction. The recess 262 has a semi-circularshape as viewed in the first direction from the other side toward theone side. The recess 262 is open toward the one end portion of thecasing 10 in the second direction. That is, the recess 262 is positionedat the third outer surface 13 of the one end portion of the casing 10 inthe second direction.

The recess 262 has a second inclined surface 262 c at the opposite sideto the open side. That is, the second inclined surface 262 c ispositioned at an inner wall surface of the recess 262. The secondinclined surface 262 c is fixed to the casing 10. The second inclinedsurface 262 c is inclined relative to the first direction. The secondinclined surface 262 c is inclined so as to be distant in the seconddirection from the one side toward the other side from the third outersurface 13 (specifically, the outer surface of the lid 10B) of the oneend portion of the casing 10 in the second direction as extending in thefirst direction from the one side to the other side.

In a state where the developing cartridge 1 is attached to the drumcartridge 2, the second inclined surface 262 c is movable together withthe casing 10 and the developing roller 30 relative to thephotosensitive drum 21 between a third position and a fourth position inthe first direction and the second direction.

8. Movement of Each Component in Second Embodiment at the Time ofSwitching Between Contacting State and Separated State

Movement of each component for the contact and the separation at thetime of switching the state of the image-forming apparatus 100 accordingto the second embodiment between the contacting state and the separatedstate will be described while referring to FIGS. 14 to 19 . FIG. 14 is across-sectional view of the developing cartridge 4 according to thesecond embodiment in the contacting state, taken along a planeperpendicular to the third direction. FIG. 15 is a view of thedeveloping cartridge 4 according to the second embodiment in thecontacting state as viewed in the first direction from the other sidetoward the one side. FIG. 16 is a perspective view of the developingcartridge 4 according to the second embodiment in the contacting state.FIG. 17 is a cross-sectional view of the developing cartridge 4according to the second embodiment in the separated state, taken along aplane perpendicular to the third direction. FIG. 18 is a view of thedeveloping cartridge 4 according to the second embodiment in theseparated state as viewed in the first direction from the other side tothe one side. FIG. 19 is a perspective view of the developing cartridge4 according to the second embodiment in the separated state.

In the image-forming apparatus 100, when the drive shaft 103 is drivento start to advance in a direction from the other end portion of thecasing 10 in the first direction toward the one end portion of thecasing 10 in the first direction, a tip end portion of the drive shaft103 enters the recess 262 and contacts the second inclined surface 262 cat a position closer to another end of the second inclined surface 262 cin the first direction.

When the drive shaft 103 further advances toward the one end portion ofthe casing 10 in the first direction, the second inclined surface 262 cis pressed in the first direction from the other side toward the oneside because of the contact of the second inclined surface 262 c withthe drive shaft 103. Hence, the contacting position between the secondinclined surface 262 c and the drive shaft 103 is gradually shifted onthe second inclined surface 262 c from the position closer to the otherend of the second inclined surface 262 c in the first direction to aposition closer to one end of the second inclined surface 262 c in thefirst direction. In accordance with this, the second inclined surface262 c is pressed in the second direction from the one side toward theother side because of the contact of the second inclined surface 262 cwith the drive shaft 103. In this way, the second inclined surface 262 cis pressed by the drive shaft 103 to thereby move in the seconddirection while moving in the first direction. Thus, the second inclinedsurface 262 c moves from the third position illustrated in FIGS. 14through 16 to the fourth position illustrated in FIGS. 17 through 19 .

Here, in the process of movement of the second inclined surface 262 cfrom the third position to the fourth position, the casing 10 and thedeveloping roller 30 move together with the second inclined surface 262c in the first direction and in the second direction. Hence, the firstinclined surface 61 a contacts the outer circumferential surface 250 ofthe second guide roller 25. In accordance with movement of the positionof the first inclined surface 61 a in the first direction from the otherside toward the one side, the second guide roller 25 gradually pushesout the first inclined surface 61 a (the casing 10) in the seconddirection from the one side toward the other side. In this way, thefirst inclined surface 61 a moves in the second direction by beingpushed by the second guide roller 25 while moving in the first directionby being pressed by the drive shaft 103. Thus, the first inclinedsurface 61 a moves from the first position illustrated in FIGS. 14through 16 to the second position illustrated in FIGS. 17 through 19 .

9. Summary of Second Embodiment

As described above, in the second embodiment, the drive shaft 103presses the second inclined surface 262 c in the direction from theother end portion of the casing 10 in the first direction toward the oneend portion of the casing 10 in the first direction. The second inclinedsurface 262 c moves from the third position (FIGS. 14 through 16 ) tothe fourth position (FIGS. 17 through 20 ) when the drive shaft 103presses the second inclined surface 262 c. Here, the pressing forcedirected in the first direction from the other side to the one side isconverted to the force directed in the second direction by the contactbetween the drive shaft 103 and the second inclined surface 262 c. As aresult, the developing roller 30 can be separated from thephotosensitive drum 21.

Further, the developing cartridge 4 according to the second embodimenthas the recess 262 positioned at the third outer surface 13 of the oneend portion of the casing 10 in the second direction. The recess 262 hasthe second inclined surface 262 c. Hence, the drive shaft 103 isinserted in the recess 262 and pushes the second inclined surface 262 c,so that the developing roller 30 can be separated from thephotosensitive drum 21.

10. Modifications

The present disclosure is not limited to the above describedembodiments, but various changes may be made, and various modificationsare conceivable.

In the above described embodiments, the elastic member 35 urges thedeveloping roller 30 in the direction from the one end portion of thecasing 10 in the first direction toward the other end portion of thecasing 10 in the first direction. However, an elastic member may urgethe casing 10 in the direction from the one end portion of the casing 10in the first direction toward the other end portion of the casing 10 inthe first direction.

In the above-described embodiments, the elastic member 35 is the coilspring. Instead, a leaf spring and a sponge are available as the elasticmember.

The drum cartridge 2 need not necessarily include the first guide roller24 and the second guide roller 25. The first inclined surface maycontact the drum frame of the drum cartridge when the first inclinedsurface moves from the first position to the second position. Further,the second inclined surface may contact the drum frame of the drumcartridge when the second inclined surface moves from the third positionto the fourth position.

The shapes of the first cam 61 and the second cam 62 is not limited tothe above-described shapes. For example, the first cam may have afrustoconical shape similar to the second cam.

Further, detailed configuration of the developing cartridge may bedifferent from that described above and illustrated in the drawings, andthe components in the above-described embodiments and modifications maybe suitably combined together as long as no technical conflicts israised.

What is claimed is:
 1. A developing cartridge attachable to a drumcartridge including a photosensitive drum, the developing cartridgecomprising: a casing configured to accommodate therein developing agent;a developing roller rotatable about a developing roller axis extendingin a first direction, the developing roller being contactable with thephotosensitive drum, the developing roller having a circumferentialsurface having one side portion and another side portion in a seconddirection crossing the first direction, the one side portion beingexposed to an outside of the casing, the another side portion beingpositioned inside the casing; and a first inclined surface positioned atan outer surface of one end portion of the casing in the seconddirection, the first inclined surface being fixed to the casing, thefirst inclined surface being inclined relative to the first direction,the first inclined surface being movable together with the casing andthe developing roller in the first direction relative to thephotosensitive drum between a first position and a second position in astate where the developing cartridge is attached to the drum cartridge,wherein, in a state where the first inclined surface is at the firstposition, the developing roller is in contact with the photosensitivedrum, and wherein, in a state where the first inclined surface is at thesecond position, the developing roller is in separation from thephotosensitive drum.
 2. The developing cartridge according to claim 1,wherein the first inclined surface has one end edge and another end edgein the first direction, and wherein a first distance in the seconddirection between the one end edge of the first inclined surface and theouter surface is smaller than a second distance in the second directionbetween the another end edge of the first inclined surface and the outersurface.
 3. The developing cartridge according to claim 1 or 2, furthercomprising a second inclined surface positioned at the outer surface,the second inclined surface being fixed to the casing, the secondinclined surface being inclined relative to the first direction, thesecond inclined surface being positioned away from the first inclinedsurface in the first direction, the second inclined surface beingmovable together with the first inclined surface in the first directionrelative to the photosensitive drum between a third position and afourth position in the state where the developing cartridge is attachedto the drum cartridge, wherein, in the state where the first inclinedsurface is at the first position, the second inclined surface is at thethird position and the developing roller is in contact with thephotosensitive drum, and wherein, in the state where the first inclinedsurface is at the second position, the second inclined surface is at thefourth position and the developing roller is in separation from thephotosensitive drum.
 4. The developing cartridge according to claim 3,wherein the second inclined surface has one end edge and another endedge in the first direction, wherein a third distance in the seconddirection between the one end edge of the second inclined surface andthe outer surface is smaller than a fourth distance in the seconddirection between the another end edge of the second inclined surfaceand the outer surface.
 5. The developing cartridge according to claim 3,wherein the casing has one end portion and another end portion in thefirst direction, wherein the drum cartridge is attachable to a main bodyof an image-forming apparatus, wherein the main body includes a driveshaft extending in the first direction, the drive shaft being configuredto advance and retract in the first direction by receiving a drivingforce from the main body, the drive shaft being configured to press thesecond inclined surface in a direction from the another end portion ofthe casing in the first direction toward the one end portion of thecasing in the first direction, and wherein, when the drive shaft pressesthe second inclined surface, the second inclined surface moves from thethird position to the fourth position.
 6. The developing cartridgeaccording to claim 5, further comprising a recess positioned at theouter surface of the one end portion of the casing in the seconddirection, and wherein the recess has the second inclined surface. 7.The developing cartridge according to claim 6, wherein, in a state wherethe drum cartridge is attached to the main body with the developingcartridge attached to the drum cartridge, the first inclined surface isat the second position and the second inclined surface is at the fourthposition in a state where a pressing force is applied to the secondinclined surface from the drive shaft, and the first inclined surface isat the first position and the second inclined surface is at the thirdposition in a state where the pressing force is not applied to thesecond inclined surface from the drive shaft.
 8. The developingcartridge according to claim 1, wherein the casing has one end portionand another end portion in the first direction, the another end portionof the casing in the first direction having an outer surface, thedeveloping cartridge further comprising a pressure receiving surfacepositioned at the outer surface of the another end portion of the casingin the first direction, the pressure receiving surface being configuredto receive a pressing force directed in a direction from the another endportion of the casing in the first direction toward the one end portionof the casing in the first direction.
 9. The developing cartridgeaccording to claim 8, wherein, when the pressure receiving surfacereceives the pressing force, the first inclined surface moves from thefirst position to the second position.
 10. The developing cartridgeaccording to claim 9, wherein the drum cartridge is attachable to a mainbody of an image-forming apparatus, the main body including a driveshaft extending in the first direction, the drive shaft being configuredto advance and retract in the first direction by receiving a drivingforce from the main body, the drive shaft being configured to press thepressure receiving surface in the direction from the another end portionof the casing in the first direction toward the one end portion of thecasing in the first direction, and wherein, when the drive shaft pressesthe pressure receiving surface, the first inclined surface moves fromthe first position to the second position.
 11. The developing cartridgeaccording to claim 10, wherein the developing roller comprises: a rollerbody extending in the first direction; and a developing roller shaftrotatable together with the roller body, the developing roller shafthaving one end portion and another end portion in the first direction,the developing cartridge further comprising: a collar positioned at theone end portion of the developing roller shaft in the first direction,the collar rotatably supporting the developing roller shaft; and anelastic member positioned between the roller body and the collar in thefirst direction.
 12. The developing cartridge according to claim 11,wherein the elastic member is a spring.
 13. The developing cartridgeaccording to claim 12, wherein the spring is a coil spring.
 14. Thedeveloping cartridge according to claim 11, wherein, when the drumcartridge is attached to the main body in the state where the developingcartridge is attached to the drum cartridge, the elastic member urgesone of the developing roller and the casing in a direction from the oneend portion of the casing in the first direction toward the another endportion of the casing in the first direction.
 15. The developingcartridge according to claim 11, wherein the collar is electricallyconnected to the developing roller.
 16. The developing cartridgeaccording to claim 11, wherein, when the drum cartridge is attached tothe main body in the state where the developing cartridge is attached tothe drum cartridge, a direction in which the elastic member urges one ofthe developing roller and the casing is opposite to a direction in whichthe drive shaft presses the pressure receiving surface.
 17. Thedeveloping cartridge according to claim 11, wherein, when a supply ofthe driving force from the main body to the drive shaft is stopped in astate where the drum cartridge is attached to the main body with thedeveloping cartridge attached to the drum cartridge, the first inclinedsurface moves from the second position to the first position by anurging force of the elastic member.
 18. The developing cartridgeaccording to claim 10, wherein, in a state where the drum cartridge isattached to the main body with the developing cartridge attached to thedrum cartridge, the pressure receiving surface is overlapped with thedrive shaft in the first direction both when the first inclined surfaceis at the first position and when the first inclined surface is at thesecond position.
 19. The developing cartridge according to claim 10,wherein, in a state where the drum cartridge is attached to the mainbody with the developing cartridge attached to the drum cartridge, thefirst inclined surface is at the second position in a state where thepressing force is applied to the pressure receiving surface from thedrive shaft, and the first inclined surface is at the first position ina state where the pressing force is not applied to the pressurereceiving surface from the drive shaft.
 20. The developing cartridgeaccording to claim 8, wherein the pressure receiving surface is a flatsurface perpendicular to the first direction.
 21. The developingcartridge according to claim 1, wherein the drum cartridge has a contactsurface contactable with the first inclined surface.
 22. The developingcartridge according to claim 21, wherein the contact surface is an outercircumferential surface of a cylindrical member whose center is arotation axis extending in a third direction crossing both the firstdirection and the second direction.
 23. The developing cartridgeaccording to claim 22, wherein the cylindrical member is rotatable aboutthe rotation axis.
 24. The developing cartridge according to claim 1,wherein the first inclined surface has one end edge and another end edgein the first direction, the first inclined surface being inclined so asto be distant in the second direction from the outer surface of the oneend portion of the casing in the second direction as extending from theone end edge of the first inclined surface to the another end edge ofthe first inclined surface.